The disclosure relates to a self-leveling multi-line laser device for generating at least two, mutually perpendicular projectable laser lines. By means of such a device, by way of example, horizontal and vertical planes can be spanned by respective one-dimensionally expanded laser beams and horizontal and vertical lines can respectively be projected for example onto wall areas or objects. These projectable lines are designated henceforth as laser lines or projected laser lines of the multi-line laser device, although the device cannot produce these lines itself, but rather only by projection of the expanded laser beam onto a wall or an object, for example.
Multi-line laser devices of this type can be used, in particular, in industry, in the craft sector and do-it-yourself sector for example for adjustment, marking, measurement and alignment tasks.
Diverse two-line laser devices are known from the prior art, which can be used to project two mutually perpendicular laser lines. In this case, either laser beams are expanded by lens elements in a plane, as a result of which a respective laser line with a useable angular range of approximately 60° to 120° can be generated. Two of these laser lines can thus be provided by combination of two laser beams and two lens elements in a 90° position with respect to one another.
A disadvantage of such two-line laser devices comprising a lens element for expanding the laser beam is, inter alia, the restricted useable angular range of the expanded laser beam of typically 60° to 120°, as a result of which only one laser cross with a single point of intersection between the two projected laser lines can be generated, and a further disadvantage is the great decrease in brightness of the laser line that can be generated toward the outer regions.
Alternatively, rotational laser devices are also commercially available, wherein a laser beam is deflected by 90° by a rapidly rotating deflection element and the optical illusion of a continuous laser line is thus generated by the laser beam rotating with the rotating deflection element. By combining two rotational laser units arranged at an angle of 90° in one device, it is thus possible to project two mutually perpendicular laser lines onto walls or objects, for example.
Disadvantages of such rotational laser devices include, inter alia, the complex mechanical construction and the high production costs associated therewith, and also the large, heavy design of such laser devices. Further disadvantages of such devices include energy consumption and wear and also the limited reliability of said devices over the lifetime.
It is an object of the present disclosure to overcome the disadvantages of the prior art and, in particular, to provide a self-leveling multi-line laser device which can project laser lines over a large angular range of at least 180° in conjunction with a small design, favorable production costs and without rotating parts.
This object is achieved by the self-leveling multi-line laser device set forth below.
Preferred embodiments are also set forth below.
The disclosure specifies a self-leveling multi-line laser device comprising at least two laser beams and at least two reflective cones, wherein the cone axes of the reflective cones are perpendicular to one another and each of the laser beams can be directed—preferably excentrically—parallel to the axis of one of the reflective cones against the vertex of said reflective cone, as a result of which at least two projectable laser lines can be generated.
One advantage of the disclosure consists in the possibility of providing, for example, two mutually perpendicular laser lines having high positional accuracy, which have better visibility in conjunction with a relatively uniform brightness distribution over this large angular range with the emitted laser energy being utilized as completely as possible. Moreover, it is possible as a further advantage, on account of the large angular coverage of the laser line of at least 180°, to produce two points of intersection (or marking crosses) of the projectable laser lines in a “180° position” with respect to one another for example on walls lying opposite one another. A further advantage of the construction according to the disclosure is that the laser energy is distributed effectively substantially only over the desired angular range—and not over 360° as in the case of the rotational lasers used hitherto in said angular range. Moreover, the construction according to the disclosure allows the particularly advantageous use of laser beam sources having non-round beam cross sections, such as, for example, of the particularly economical, reliable and cost-effective laser diodes, wherein a very uniform brightness distribution of the laser lines that can be generated can be obtained in this case. By virtue of the construction according to the disclosure, the complex, expensive and heavy rotational laser devices can be replaced in many applications.
In one preferred embodiment of the disclosure, the reflective cones can have at least partial areas of a lateral surface of a right circular cone having a cone aperture angle of 90°. It is thereby possible to ensure that a parallel-directed laser beam that is incident parallel to the cone axis of the cone partial area is expanded exactly in a plane. The use of such cone partial areas instead of a complete cone makes it possible to save material and structural space.
In a further preferred embodiment of the disclosure, at least one of the reflective cones can have non-reflective partial areas. Thus, it may be desired, for example, for a sector of the cone to be blackened, matted or not reflectively coated, in order thus to limit the laser line that can be generated in the angular range for example to 180° or 200° or 240° or some other value and to prevent “spurious light” and undesired reflections.
In a further preferred embodiment of the disclosure, it is possible that at least one laser beam can be generated by a laser diode as laser beam source and can preferably be collimated by at least one collimating optical element, in particular a collimator lens. The use of laser diodes as laser beam sources allows particularly cost-effective production and also a more compact design of the multi-line laser device. In this case, by means of the collimating optical element, the divergent laser beam as emitted by laser diodes can be collimated, that is to say directed parallel, as a result of which a more exact projection geometry and hence a more exact laser line can be obtained using a right circular cone.
In a further preferred embodiment of the disclosure, it is possible that a laser beam having an elliptical beam cross section can be generated by the laser diode, wherein the center axis of the elliptical beam cross section has a parallel offset relative to the cone axis and is spaced apart from the cone axis in the direction of the short semiaxes of the elliptical beam cross section and, preferably, the distance between the center axis of the elliptical beam cross section and the cone axis is less than or equal to, in particular less than, the length of the short semiaxes of the elliptical beam cross section. It is thereby possible to obtain a particularly high brightness and uniform brightness distribution over an angular range of more than 180°. In a further preferred embodiment of the disclosure, a diaphragm can also be arranged in the beam path of the laser diode. It is thereby possible to balance the brightness distribution of the projectable laser line and to avoid “spurious light” that could pass through the reflective cone without being reflected. In a further preferred embodiment of the disclosure, it is possible that at least two laser beams can preferably be coupled out from a laser beam source, preferably from a laser diode, by means of beam splitting by a partly reflective optical element. This can be achieved in the simplest case by means of a partly transmissive mirror arranged at an angle of 45° with respect to the laser beam to be split. Alternatively, for example partially reflectively coated elements, prisms or intermittently operating, for example mechanical or electro-optical elements could be employed for beam splitting. It is thereby possible to save a laser beam source. This is advantageous particularly if, for example, a green laser line is intended to be provided by the multi-line laser device, since laser beam sources that emit in the green spectral range currently are still relatively expensive. In a further preferred embodiment of the disclosure, the useable angular range of the laser line emitted from the reflective cone is at least 180° (see angle 20 of FIG. 4), preferably greater than 200°, in particular greater than 200° in the horizontal plane (see angle 21 of Figure and greater than 240° in the vertical plane (see angle 22 of FIG. 4). It is thereby possible to provide laser lines which cover more than a semicircle and intersect at two points, in which case areas of application can additionally be opened up. By way of example, in the case of an angular range of more than 240° in the vertical plane in numerous applications including when the multi-line laser device is mounted on a stand, it is possible to provide a usually complete plumb line on a wall, said plumb line extending from the ceiling to the floor.
In a further preferred embodiment of the disclosure, it is possible that an optical system carrier, on and/or in which the laser beam source(s), the collimating optical element(s) and the reflective cones can be mounted, is alignable—preferably self-aligning—in a gravitational field, as a result of which the laser beams and cone axes are alignable in the direction of the gravitational vector or perpendicularly thereto. Such a construction makes it possible to provide horizontal and vertical laser lines particularly expediently and exactly.
In a further preferred embodiment of the disclosure, the self-leveling multi-line laser device can have a third reflective cone or a third device for laser beam expansion, in particular a cylindrical lens or a diffractive optical element (DOE) for generating a further, preferably vertical, laser line, preferably perpendicular to the two other laser lines. It is thus conceivable, for example, by means of extension by a third laser beam and third reflective cone, to generate a third laser line, which spans a third spatial plane and is perpendicular to the two other laser lines. Furthermore, it is particularly advantageously possible to expand a laser beam by means of a cylindrical lens or a diffractive optical element (DOE) in a third spatial plane and thus to generate a third laser line perpendicular to the two other laser lines, wherein such an embodiment can be realized in a particularly space-saving and cost-effective manner.
In a further preferred embodiment of the disclosure, it is possible that the laser beam source(s), the collimating optical element(s) and the reflective cones can be mounted on and/or in an optical system carrier, wherein the optical system carrier is embodied in self-leveling fashion and is preferably suspended in oscillating fashion on preferably two mutually perpendicular bearing axes aligned substantially horizontally in an operating state. A self-leveling capability of the multi-line laser device can thereby be achieved in a particularly advantageous manner.
In a further preferred embodiment of the disclosure, the optical system carrier can have a vibration damping arrangement, preferably a magnetic damping arrangement, in particular an eddy-current damping arrangement. Such a vibration damping arrangement makes it possible to considerably improve the settling duration and the achievable setting accuracy of the laser lines, and thereby to increase practical benefits and efficiency during use in practice.